Murphy is the kind of player who you can deliver extreme yet compelling arguments for or against the Mets keeping long-term.

PRO — In an age when it has become hard to hit the ball successfully against elite pitching and shifts, Murphy does. He never has been cowed hitting in Citi Field. He is a hard worker. He provides some defensive flexibility.

CON — He hits, yes, but not for enough impact. His defense anywhere you put him is below average. His instincts are, at best, dubious. He will be 30 next April, and there are a glut of wretched, multi-year contracts for second basemen already in the game.

What to do with Murphy is a key decision in this pivotal Mets offseason. To date, they have shunned signing him long-term, yet — according to multiple executives on other teams — their requests in trade talks suggest he is not a player they want to move.

But it is getting closer and closer to decision time for the Mets with Murphy. He can be a free agent after next season. So do they trade him? Play out the 2015 season with him? Or do they sign him to, say, a four-year, $40 million-ish deal to make him part of the firmament moving forward?

The sense I get is the Mets once again will make him available this offseason and once again ask for a significant return. They see a weak free-agent market for hitters. So, in supply and demand, the Mets think they have what is in short supply, so they will make a big demand.

If they are successful in dealing Murphy, the Mets could begin next year with Wilmer Flores at second as a placeholder, hoping Dilson Herrera is ready to join the club in June or July and provide a long-term answer at the position.

But, as one NL scout said, “This is a club that struggles to score, so they better have some answers/pieces behind him to allow them to construct an offense. If they can move him for some near-major-league-ready offensive help, then maybe it makes sense, but he might just get a little better if they were actually able to add some players around him.”

If the Mets can’t trade Murphy in the offseason, they can begin the year with him at second and reconsider dealing him during the 2015 campaign, particularly if Herrera demonstrates that he should be summoned. One question is if the Mets will be keen to pay Murphy the $8 million-$9 million he likely will earn in his final season of arbitration eligibility or whether they would rather redirect that money elsewhere.

As for blowing a chance to sign Murphy long-term, one outside executive summed it up this way: “I don’t see the value of the Mets signing him now. It is not like he is going to hit 25 homers next year and change his value much. Whatever you will pay for him on a long-term contract now, you can do after next season, too.”

Also, indications are the Mets are not showing much enthusiasm to have Murphy join David Wright and Curtis Granderson as the long-term foundational pieces of the lineup, in part, because the deals for Wright and Granderson look as if they could go rather bad.

For better or worse, this is a front office that believes in drawing walks and hitting homers, areas Murphy does not excel. Murphy’s defense at second also has regressed, whether your use old stats (15 errors — five more than any other second baseman), new stats (his minus-11 for defensive runs saved was the worst of any of the second basemen who had played at least 500 innings at the position) or eyesight (scouts had taken to counting how many relays Murphy fumbles trying to quickly exchange from glove to hand without ever being charged with an error).

In addition, Mets officials have noticed how many multi-year second base deals went rotten. Dan Uggla (five years at $62 million) might be done as a player with one year still remaining on that deal. Arizona (Aaron Hill, three years at $35 million), Milwaukee (Rickie Weeks, four years, $38.7 million) and Cincinnati (Brandon Phillips, six years, $72.5 million) each tried mightily to get out of as much of its second base pacts as possible, without success. And we will see how much larger deals for better players such as Robinson Cano and Dustin Pedroia turn out.

Conversely, teams have been interested in Murphy. The Padres, for example, tried on multiple occasions to obtain him, offering Luke Gregerson last offseason before using the righty reliever to get Seth Smith from Oakland. A good deal of that pursuit was influenced by San Diego’s VP of baseball operations, Omar Minaya, who was the Mets’ general manager in 2006 when Murphy was drafted and who always has been a fan of the player.

But San Diego is not alone in seeing how Murphy can be an asset. He leads the NL in hits. There were executives who told me they see his best value as a Ben Zobrist type — playing regularly, but at multiple positions — but without Zobrist’s defensive acumen. The Padres, for example, were going to move him all over the field in 2014 and see how he handled third base, in particular, to gauge if he could replace Chase Headley, who was in his final year before free agency. Clubs such as Tampa Bay and Oakland gravitate to players like this.

“I think he is a pretty valuable bat, especially where offense is headed,” one Al executive said. “I don’t know that he is cornerstone, but he is a pretty valuable piece on a good team.”